Eight states have passed laws requiring research institutions to offer healthy dogs and cats up for adoption, rather than killing them. Ringo the beagle loves all the things every dog would: Running in the yard, rides in the car and the frequent snack. “He’s just so happy to sit right in your lappy,” his owner, Amy Bleich, an engineer in Edgewater, Maryland, said. You’d never know that Ringo, now five years old, had lived the entire first two years of his life inside a small cage at a nearby medical…